This application claims the priority of German Patent Application No. 197 47 962.6, filed Oct. 30, 1997, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a torque converter connection to a crankshaft in the drive train of a motor vehicle using a shaft-hub connection provided with lengthwise teeth for releasable connection of a crankshaft with a coaxial hydrodynamic torque converter.
It is already known to connect a torque converter to a crankshaft through a clutch disk. German Patent Document DE 195 22 869 A1 describes such a clutch disk, so designed that the connecting bolts between the clutch disk and the torque converter extend in the radial direction for easier assembly.
A connection between the crankshaft and the torque converter by means of a clutch disk basically requires costly assembly work.
It is already known to use a splined connection for transmitting torque. German Patent Document DE 699916 and U.S. Pat. No. 2,297,390 describe such a splined connection used in propeller driving shafts. The splined connection disclosed in these documents is so designed to transmit torque while transmitting stresses in an axial direction.
However, such a splined connection as disclosed in Germany Patent Document DE 699916 and U.S. Pat. No. 2,297,390 has not been previously used to provide a connection between a torque convertor and a crankshaft of an engine.
Hence, an object of the invention is to provide a releasable connection between a torque converter and a crankshaft, which can be installed simply and is free of play at least during torque conversion.
This object is achieved according to the invention by providing an arrangement in a torque converter wherein the lengthwise teeth of the shaft-hub connection have tooth cross sections that increase or decrease in the lengthwise direction of the teeth.
According to the invention, a drive connection for torque transmission is provided in the drive train of an engine, such as in a motor vehicle, by a shaft-hub connection provided with lengthwise teeth for releasable connection of a crankshaft with a coaxial hydrodynamic torque converter, with the lengthwise teeth of the shaft-hub connection having tooth cross sections that increase or decrease in the lengthwise direction of the teeth.
Lengthwise toothing with an axially conical tooth shape of this kind on the shaft and hub has the advantage that freedom from play results from axial pretensioning. In addition, a connection between a crankshaft and a coaxial hydrodynamic torque converter is simple to provide by using such a shaft-hub connection. For this purpose, the crankshaft and torque converter need only be pushed together in the axial direction so that the lengthwise teeth of the shaft and hub mesh with one another.
In a preferred embodiment of the invention, the hub and shaft with lengthwise teeth are mounted on the torque converter and the corresponding element of the shaft-hub connection is mounted on the crankshaft.
This has the advantage that the torque-transmitting connection between the crankshaft and the torque converter consists of very few parts that can be assembled at low assembly cost.
This advantage is even more important in another preferred embodiment of the invention in which the shaft and/or hub with lengthwise teeth is made integral with the crankshaft.
In one advantageous embodiment of the invention, an axial force is used for axially securing the shaft-hub connection, said force resulting from converter internal pressure during the operation of the converter.
A design of this kind has the advantage that no further measures need be taken for axially securing the shaft-hub connection. The axial force in the direction of the crankshaft that results from the operation of the torque converter presses the conical lengthwise teeth into one another with zero play.
In addition, in another advantageous embodiment of the invention, the shaft and hub can be connected shapewise with one another for axially securing the shaft-hub connection.
This advantageously secures the connection between the crankshaft and the torque converter even when the torque converter is not operating and hence no internal pressure is present in the converter. Such shapewise connections between the shaft and the hub are achieved by known machine elements, for example by a tensioning spring provided in a circumferential groove of the hub or by bolts screwed into the hub in the radial direction and passing therethrough.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.